Apparatus for concentrating minerals by flotation



Sept. 15,l 1936.`

v s.- TUCKER 2,054,643

APPARATUS FOR CONCENTRATING MIERALS BY FLOTATION f Filed Jan. '21, 1956 3 Sheets-Sheet 1 Attorney;

S. TUCKER Sept. 15, 1936.

APPARATUS FOR CONCENTRATING MINERALS BY FLOTATION Filed Jan. 21, 1936 S. TUCKER sept. 15, 1936.

APPARATUS FOP; CONCENTRATING MINERALS BY FLOTATION Filed Jan. 2l, 1936 3 Sheets-Sheet 3 Patented Sept. 15, 1936 APPARATUS FOR CONCNTRATING MINERALS BY FLOTATION Stanley Tucker, London, England, assignor to Minerals Separation North American Corporation, New York, N. Y., a corporation of Maryland Application January 21, 1936, Serial No. 60,031 In Great Britain January 26, 1935 4 Claims.

This invention relates to improvements in apparatus for concentrating minerals by flotation.

In the carrying out of flotation processes, it has been customary to employ apparatus having a porous medium through which air is delivered under pressure into the ore pulp so that the air-bubbles, rising through the pulp, carry with them particles of valuble mineral and form a froth on the pulp surface which can be collected.

In such apparatus, it is customary to either fix the porous medium in the bottom of the Cell, or else movably mount it on a carrier in the midst of the pulp body, but regardless of whichever arrangement may be employed, the porous medium is liable to become chocked with sediment or blinded" over a portion of its area, thus rendering it incapable of electively serving to distribute air through the whole body of pulp. In order to recondition the apparatus for use, the porous medium must be either cleaned or renewed, thus necessitating a complete shut-down of the apparatus to permit the cleaning or renewal operation to be carried out.

Important objects of the present invention are to decrease the likelihood of the porous medium becoming clogged and to facilitate its being cleaned or renewed without necessitating a shutdown in the operation of the apparatus.

Other objects and advantages of the invention will become apparent from the following description, taken in connection with the accompanying drawings, in which- Figure 1 is a vertical longitudinal section A through the apparatus;

.Figure 2 is an end View in the plane 2-2 of Figure 1 lookin-g in the direction of the arrows;

Figure 3 is a view in the same plane but looking in the opposite direction, namely in the direction of the arrows 3--3 and showing only the face of the distributing valve;

Figure 4 is a detail of air cells taken in section upon the line 4 4 of Figure 1;

Figure 5 is a detail of the porous medium in section to an enlarged scale, and

Figure 6 is a side elevation of the discharge end of a modified form of apparatus.

Referring to Figures 1 and 2, a framework II supports flanged idlers I2, I3 which carry a horizontal cylindrical pulp vessel It having outer walls l5 and end anges I6, Il. The end ange i6 carries a concentric and conical end plate I3 having a iiared mouth I9, the minimum internal diameter of which, as shown at 20, determines the maximum liquid level within the pulp vessel Ill.

The end ange Il has bolted to it an end plate 2I to which is secured, concentrically with tne axis of the pulp Vessel, a-valve plate 22. Disposed around the interior of the pulp vessel I4 there are a number of triangular tubular air cells 23 which, as shown in Figure 4, are disposed with one apex 24 of the triangle abutting upon the outer wall I5 of the pulp Vessel and with a flat base portion 25 of the triangular air cell facing towards the interior of the pulp vessel, The bases 25 abut upon one another, corner to corner, and they contain perforations 26 over which is stretched a porous fabric 2l. The air cells are held in situation by means of bolts 20 and they are connected -at one end, by means of pipes 29 which pass through the end plate 2i, with the valve element 22.

It will be seen that the porous material 2l is, in eect, stretched all around the interior of the pulp chamber. -The porous material consists of rubber sheeting which has been pierced with double conical holes 30, as shown in Figure 5. Between the cells or pipes 23 a water-tight joint is made by rubber tubing 4l similar to the material known as draught tubing.

The valve element 22 rotates with the pulp chamber and eachA of the pipes 29 opens into a port 3l in the end face of the valve element 22. An air distributing plate 32 is held concentric with the valve element 22 and is pressed against it by springs 33 which are backed up by a bracket 34 carried on the framework ll. The distributing plate contains an air port 35 which is connected to an air line 36 and the dimensions ofthe air port 35 are such as to ensure that the ports 3l in the rotating valve element are connected to the air pressure supply during the time in which the air cells to which they are coupled lie beneath the pulp level in the pulp vessel I4.

It will be observed that in the centre of the valve element 22 there is secured, concentric with the pulp vessel I4, a driving shaft 31 and this is connected to reducing gear 38, 39 and thence by other reduction trains (not shown in the drawings) to the power supply.

Pulp outlets 40 pass through the end wall 2| of the pulp vessel, said outlets being disposed upon the largest radius which lies within the internal surface in the porous medium 21. The pulp outlets are connected to delivery pipes AI which serve to drain tailings from the apparatus into a launder 22. The pulp outlet pipes 4I drain out pulp from the pulp chamber 4only at such time as that in which they lie beneath the liquid level in the chamber and therefore they do not require to be provided with any controlling valves.

The pipes 4I are made readily removable so that several sets of pipes of differing sizes may be provided which are readily interchangeable with one another, the size of pipe employed being chosen to suit the volume of pulp being treated. Minor variations in rate of pulp iiow are taken care of automatically because if the pulp level rises in the pulp vessel I4 the number of tailings discharge pipes 4I which are active, increases.

The pulpv in the pipe 43 enters the pulp vessel I4 through the open discharge mouth I9 and delivers pulp to the interior of the chamber below the pulp level and nearer to the mouth I9 than to-the plate 2I.y

In the operation of this apparatus ore pulp which is to be subjected to otation is delivered through the pipe 43 to the interior of the pulp vessel I4 until it reaches a level such as that indicated by the line 44 in the drawings, this line lyingsomewhat below the level ofthe bottom 20 of the mouth I9. Air is admitted through the air line 36 to the cells 23, and the valve 22, 32 controls the delivery so that only those cells which lie below the pulp level receive any air. 'I'he air issuing beneath the pulp level through the apertures 30 (Figure 5) aerates the pulp and produces a froth which overflows through the mouth I9, while tailings escape through the discharge pipes 4I, when these lie beneath the pulp level, into the launder 42.

The modification illustrated in Figure 6 shows an air distributing plate 50 held in position by convenient locking device such as the arm 52.

which extends down to an adjusting screw 53 by which the plate may be advanced or retarded. With this construction the'cylinder could be rotated not by the shaft 31 but by means of chain and sprockets operating on one of the shafts of the idlers I3 or by direct attachment to the pulp vessel I4 thus eliminating the train of gears.' In this way the main vessel would float on the idlers and alignment is simplied, as well as which wear on the idlers does not affect the alignment of the air distributing valve.l Moreover this construction makes it easy to mount the pulp vessel on an inclined axis and to vary the inclination if this is found desirable.

Any necessary'reagents can be introduced into the pulp before delivering it to the flotation vessel I4 or a special reagent delivery pipe can be added if desired to carry the reagents into the pulp in the interior of. the vessel.

The movement of the porous medium during the flotation operation isadvantageous because it tends to prevent any collection of sediment of heavier or coarser particles at any one place on the porous bottom. Moreover, any coarser particles which may settle and are valuable will be carried up the side of the flotation vessel as far as the froth level where they are launched on the froth by gravity, and it is a feature of the apparatus herein described that coarser, that is to say less nely ground pulp can be efficiently floated.

Moreover, in the event of it lbeing necessary to run the plant for a portion only of. a day the machine can be left with a load of material in it and efficiently started up on the resumption of work because the movement of the flotation vessel will distribute the ore again into the liquid.

flotation vessel can be stopped in its rotation with` the particular porous unit which requires attention above the pulp level, and this unit can then be removed and replaced rapidly. Moreover, the distributor valve can be so designed, if desired, that air can be applied to selected units while they are above the froth level with the object of blowing the porous medium clear of any obstructions in the pores and this can be done, if desired, under the control of the operator without stopping the machine. Even while the rotation of the flotation vessel is interrupted for renewal or replacement of a unit, flotation can still go on uninterruptedly,

Although a particular tubular construction of porous medium has been hereinbefore described by'way of example it will be understood that other constructions may be adopted and that the porous medium may be constituted if desired by a continuous band of material passing beneath the pulp. It is one advantage of the presn pulp vessel, to propel the froth outwardly. Inf stead of feeding the ore pulp in at the same end of the apparatus as the froth discharge it may be fed in through the opposite end, if desired.

If desired valves may be provided to control the tailings outlets as Well as the air inlets. 4A valve for this purpose might be made, similar to the valve for the air inlets but on an increased scale, or alternatively a non-retum valve in each tailings outlet could be provided which would close automatically when the outlet came above the pulp level and would thus prevent any tendency of tailings to drip back out of the outlets into the pulp within the vessel.

I claim:

1. A flotation apparatus comprising a flotation vessel mounted for rotation about a given axis and having a froth-discharge opening at one end thereof and including a porous wall-like structure adapted to support an ore pulp for treatment, a plurality of air cells grouped about and movable with said wall-like structure and communicating with said vessel by way of individual portions of that structure, valve means operating incident to rotation of said vessel for opening and closing successive air cells to a source of air supply, and tailings-discharge means communicating with said vessel and operable to relieve that vessel of tailings at a point well below the pulp level.

2. A flotation apparatus comprising a flotation vessel mounted for rotation about a given axis and having a froth-discharge opening at one end thereof and including a porous wall-like struc-l ture adapted to support an ore pulp for treatment, a plurality of air cells grouped about and movable with said wall-like structure and communicating with said vessel by way of individual portions of that structure, valve means operating incident to rotation of said vessel for opening and closing successive air cells to a source of air supply, and tailings-discharge means communicating with said vessel and operable to relieve that vessel of tailings at a point well below the'pulp level, said tailings-discharge means being characterized by a series of outlets grouped about said axis of rotation and communicating with said vessel at points in proximity to said wall-like structure and successively operable incident to rotation of said vessel.

3. A otationapparatus .comprising a otation vessel mounted for rotation about a given axis and including a pair of end walls one of which is provided with a froth-discharge opening and further including a plurality of porous elements grouped about said axis and collectively forming a porous wall-like structure adapted to support an re pulp for treatment, a plurality of air cells grouped about and movable with said Wall-like structure and communicating with said vessel by way of said porous elements, each of said cells including one of said porouselements, means for removably supporting each of the said cells and its included porous elements in an operative position intermediate said end walls, valve means operating incident to rotation of said vessel for opening and closing successive air cells to a source e of air supply, and tailings-discharge means com-` municating with said vessel and operable to relieve that vessel of tailings at a point well below the pulp level.

4. A otation apparatus comprising a notation vessel mounted for rotation about a given axis and including a pair of end walls one of which is provided with -a froth-discharge opening and further including a plurality of porous elements grouped about said axis and collectively forming.

a porous wall-like structure adapted to support an ore pulp for treatment, a plurality of air cells grouped about and movable with said wall-like structure and communicating with said vessel by way of said porous elements, each of said cells including one of said porous elements, means for removably supporting each of said cells and its included porous elements in an operative position intermediate said end walls. valve means operating incident to rotation of said vessel for opening and closing successive air cells to a source of air supply, and tailings-discharge means communieating with said vessel and operable to relieve that vessel of tailings at a point well below the pulplevel, said tailings-discharge means being characterized by a series of outlets grouped about said axis of rotation and communicating with said vessel at points in proximity to said walllike structure and successively operable incident to rotation of said vessel.

` STANLEYTUCKER. 

